docs: def on_finish(self, exc=None):
          """Used to initiate the garbage collection"""
          super(GarbageCollector, self).on_finish(exc)
          self._cycles_left -= 1
          if self._cycles_left <= 0:
              num_collected = gc.collect()
              self._cycles_left = self.collection_cycle
              LOGGER.debug('garbage collection run, %d objects evicted',
                           num_collected)